The invasive weed velvetleaf is taking advantage of perfect growing conditions to spread in various parts of New Zealand this summer and into autumn, warns Rural Contractors NZ vice-president Helen Slattery. She says there have been new finds of velvetleaf in mid-Canterbury, Auckland and Waikato but there are velvetleaf incursions in nearly every region.
“There are small blocks in Auckland with absentee owners that were previously in maize that are riddled with it,’’ says Helen.
A member of the mallow family, velvetleaf is notoriously hard to control; each plant can produce over 30,000 seeds which survive for a long time. If allowed to germinate it could mean 70% reductions in crops.
Helen is a member of MPI’s Velvetleaf Steering group, representing rural contractors. “As contractors we have particular concerns because we work on a variety of properties and the last thing we want to do is help spread this pest.” Contractors should report any velvetleaf and clean down machinery between farms.
Velvetleaf has been declared a pest plant in Waikato Regional Council’s Pest Management Plan, giving the Council power to direct and manage it. Helen Slattery says Auckland Council had not specifically identified velvetleaf as a pest plant but it was now starting to get to grips with the weed with several heavy infestations in the region.
Thousands of plants can appear on infested properties particularly after land is cultivated. Seeds can be produced from plants at 15cm tall but plants can grow to 2m. Stock eating velvetleaf seeds in maize provide a source of spread as seeds are not killed by being digested. Seeds also survive the ensiling process.
The South Island has a different strain of velvetleaf and appears to produce less seeds and while still a concern, it appears it is less invasive than the one found in the North Island.
Helen Slattery continues reminding rural contractors to be alert to velvetleaf and to maintain machinery hygiene and bio-security practices especially at this time of the year when it presents most risk of being spread. Some sprays are effective but have to be applied